U.S. patent number 8,747,416 [Application Number 14/061,554] was granted by the patent office on 2014-06-10 for low profile electrodes for an angioplasty shock wave catheter.
This patent grant is currently assigned to Shockwave Medical, Inc.. The grantee listed for this patent is Shockwave Medical, Inc.. Invention is credited to John M. Adams, Doug Hakala, Khoi T. Le, Show-Mean Steve Wu.
United States Patent |
8,747,416 |
Hakala , et al. |
June 10, 2014 |
Low profile electrodes for an angioplasty shock wave catheter
Abstract
Described herein are low-profile electrodes for use with an
angioplasty shockwave catheter. A low-profile electrode assembly
may have an inner electrode, an insulating layer disposed over the
inner electrode such that an opening in the insulating layer is
aligned with the inner electrode, and an outer electrode sheath
disposed over the insulating layer such that an opening in the
outer electrode sheath is coaxially aligned with the opening in the
insulating layer. This layered configuration allows for the
generation of shockwaves that propagate outward from the side of
the catheter. In some variations, the electrode assembly has a
second inner electrode, and the insulating layer and outer
electrode may each have a second opening that are coaxially aligned
with the second inner electrode. An angioplasty shockwave catheter
may have a plurality of such low-profile electrode assemblies along
its length to break up calcified plaques along a length of a
vessel.
Inventors: |
Hakala; Doug (Woodinville,
WA), Adams; John M. (Snohomish, WA), Le; Khoi T. (San
Jose, CA), Wu; Show-Mean Steve (Fremont, CA) |
Applicant: |
Name |
City |
State |
Country |
Type |
Shockwave Medical, Inc. |
Fremont |
CA |
US |
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Assignee: |
Shockwave Medical, Inc.
(Fremont, CA)
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Family
ID: |
50026202 |
Appl.
No.: |
14/061,554 |
Filed: |
October 23, 2013 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20140052147 A1 |
Feb 20, 2014 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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13831543 |
Mar 14, 2013 |
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61680033 |
Aug 6, 2012 |
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Current U.S.
Class: |
606/128 |
Current CPC
Class: |
A61B
17/2202 (20130101); A61B 17/22022 (20130101); A61B
2017/22021 (20130101); A61B 2017/22028 (20130101); A61B
2017/22051 (20130101); A61B 2017/22001 (20130101); A61B
2017/22062 (20130101); A61B 2017/22025 (20130101) |
Current International
Class: |
A61B
17/22 (20060101) |
Field of
Search: |
;606/48,50,127,128,159,167,170,191,192-194,196-198 ;601/2,4
;604/22 |
References Cited
[Referenced By]
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WO |
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WO |
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Other References
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Primary Examiner: McEvoy; Thomas
Assistant Examiner: Papeika; Rachel S
Attorney, Agent or Firm: Morrison & Foerster LLP
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation application of U.S. application
Ser. No. 13/831,543, entitled LOW PROFILE ELECTRODES FOR AN
ANGIOPLASTY SHOCK WAVE CATHETER, filed Mar. 14, 2013 which claims
priority to U.S. Provisional Patent Application Ser. No.
61/680,033, filed Aug. 6, 2012, which are hereby incorporated by
reference in their entirety and for all purposes.
Claims
What is claimed as new and desired to be protected by Letters
Patent of the United States is:
1. A device for generating shockwaves comprising: an axially
extending elongate member; a balloon surrounding a portion of the
elongate member, said balloon being fillable with a conductive
fluid; a first wire extending along an outside surface of the
elongate member terminating in a first inner electrode at a first
side location within the balloon; a second wire extending along the
outside surface of the elongate member terminating in a second
inner electrode located at a second side location radially across
the elongate member from the first inner electrode; a
cylindrically-shaped insulating sheath having a first aperture and
a second aperture, the insulating sheath disposed around the first
and second inner electrodes such that the first aperture of the
insulating sheath is located over the first inner electrode and the
second aperture of the insulating sheath is located over the second
inner electrode; and an outer electrode sheath having a first
aperture and a second aperture, the outer electrode sheath disposed
around the insulating sheath such that the first aperture of the
outer electrode sheath is aligned with the first aperture of the
insulating sheath and the second aperture of the outer electrode
sheath is aligned with the second aperture of the insulating
sheath, and arranged so that when the balloon is filled with the
conductive fluid and a voltage is applied across the first and
second inner electrodes, a current flows in series from the first
inner electrode to the outer electrode sheath to the second inner
electrode such that a first shockwave is initiated from the first
side location and a second shockwave is initiated from the second
side location.
2. The device of claim 1, wherein the outer surface of the elongate
member has a first groove and a second groove that each extend
along a length of the elongate member, wherein the first wire is
slidably disposed within the first groove and the second wire is
slidably disposed within the second groove.
3. The device of claim 1, wherein the first inner electrode is
crimped over an electrically conductive portion of the first wire
and the second inner electrode is crimped over an electrically
conductive portion of the second wire.
4. The device of claim 3, wherein the first inner electrode is a
first hypotube that is crimped over the first wire and the second
inner electrode is a second hypotube that is crimped over the
second wire.
5. The device of claim 1, wherein the elongate member has a
guidewire lumen extending therethrough.
6. A system for generating shockwaves comprising: an axially
extending elongate member; a balloon surrounding a portion of the
elongate member, said balloon being fillable with a conductive
fluid; a first electrode assembly at a first location along the
length of the elongate member, the first electrode assembly having
a first inner electrode, a second inner electrode, and an outer
electrode and configured to initiate shockwaves at two
circumferentially opposite locations; and a second electrode
assembly at a second location along the length of the elongate
member, the second electrode assembly having a first inner
electrode, a second inner electrode, and an outer electrode and
configured to initiate shockwaves at two circumferentially opposite
locations wherein the second inner electrode of the first electrode
assembly and the first inner electrode of the second electrode
assembly are connected and wherein when the balloon is filled with
the conductive fluid and a voltage is applied across the first
inner electrode of the first electrode assembly and the second
inner electrode of the second electrode assembly, a current flows
in series from the first inner electrode to the outer electrode to
the second inner electrode of the first electrode assembly to the
first inner electrode to the outer electrode to the second inner
electrode of the second electrode assembly such that a first pair
of shockwaves is generated at the two circumferentially opposite
locations of the first electrode assembly and a second pair of
shockwaves is generated at the two circumferentially opposite
locations of the second electrode assembly.
7. The system of claim 6, further comprising: a third electrode
assembly at a third location along the length of the elongate
member, the third electrode assembly having a first inner
electrode, a second inner electrode, and an outer electrode and
configured to initiate shockwaves at two circumferentially opposite
locations.
8. The system of claim 7, further comprising: a fourth electrode
assembly at a fourth location along the length of the elongate
member, the fourth electrode assembly having a first inner
electrode, a second inner electrode, and an outer electrode and
configured to initiate shockwaves at two circumferentially opposite
locations.
9. The system of claim 8, further comprising: a fifth electrode
assembly at a fifth location along the length of the elongate
member, the fifth electrode assembly having a first inner
electrode, a second inner electrode, and an outer electrode and
configured to initiate shockwaves at two circumferentially opposite
locations.
10. The system of claim 9, further comprising a voltage pulse
generator having first, second, and third channels, and a return
connector, and wherein the first channel is selectively connectable
to the first electrode assembly, the second channel is selectively
connectable to the third electrode assembly, the third channel is
selectively connectable to the fourth electrode assembly, and the
return connector is connected to the second, third, and fifth
electrode assemblies.
11. The system of claim 9, wherein the second inner electrode of
the first electrode assembly is connected to the first inner
electrode of the second electrode assembly, the second inner
electrode of the fourth electrode assembly is connected to the
first inner electrode of the fifth electrode assembly, and the
second inner electrodes of the second, third, and fifth electrode
assemblies are connected.
12. The system of claim 11, wherein when the balloon is filled with
the conductive fluid and a voltage is applied across the first and
second inner electrodes of the third electrode assembly, a current
flows from the first inner electrode to the outer electrode to the
second inner electrode of the third electrode assembly such that a
pair of shockwaves is generated at the two circumferentially
opposite locations of the third electrode assembly.
13. The system of claim 11, wherein when the balloon is filled with
the conductive fluid and a voltage is applied across the first
inner electrode of the fourth electrode assembly and the second
inner electrode of the fifth electrode assembly, a current flows
from the first inner electrode to the outer electrode to the second
inner electrode of the fourth electrode assembly to the first inner
electrode to the outer electrode to the second inner electrode of
the fifth electrode assembly such that a first pair of shockwaves
is generated at the two circumferentially opposite locations of the
fourth electrode assembly and second pair of shockwaves is
generated at the two circumferentially opposite locations of the
fifth electrode assembly.
14. A system for generating shockwaves comprising: an axially
extending elongate member; a balloon surrounding a portion of the
elongate member, said balloon being fillable with a conductive
fluid; a first electrode assembly at a first location along the
length of the elongate member, the first electrode assembly having
a first inner electrode, a second inner electrode, and an outer
electrode and configured to initiate shockwaves at two different
locations; a second electrode assembly at a second location along
the length of the elongate member, the second electrode assembly
having a first inner electrode, a second inner electrode, and an
outer electrode and configured to initiate shockwaves at two
different locations, wherein said first and second electrode
assemblies are connected in series; a third electrode assembly at a
third location along the length of the elongate member, the third
electrode assembly having a first inner electrode, a second inner
electrode, and an outer electrode and configured to initiate
shockwaves at two different locations; a fourth electrode assembly
at a fourth location along the length of the elongate member, the
fourth electrode assembly having a first inner electrode, a second
inner electrode, and an outer electrode and configured to initiate
shockwaves at two different locations, wherein said third and
fourth electrode assemblies are connected in series; and a voltage
pulse generator having first and second channels and a return
connector, and wherein the first channel is selectively connectable
to the first electrode assembly and the second channel is
selectively connectable to the third electrode assembly, and the
return connector is connected to the second and fourth electrode
assemblies and configured to selectively energize one of the first
and second serially connected electrode assemblies and the third
and fourth serially connected electrode assemblies.
15. The system of claim 14, wherein the second inner electrode of
the first electrode assembly is connected to the first inner
electrode of the second electrode assembly and the second inner
electrode of the third electrode assembly is connected to the first
inner electrode of the fourth electrode assembly, and the second
inner electrodes of the second and fourth electrode assemblies are
connected to the return connector.
16. The system of claim 15 further comprising: a fifth electrode
assembly at a fifth location along the length of the elongate
member, the fifth electrode assembly having a first inner
electrode, a second inner electrode, and an outer electrode and
configured to initiate shockwaves at two different locations and
wherein the voltage pulse generator includes a third channel
selectively connectable to the fifth electrode assembly.
Description
BACKGROUND
Currently, angioplasty balloons are used to open calcified lesions
in the wall of an artery. However, as an angioplasty balloon is
inflated to expand the lesion in the vascular wall, the inflation
pressure stores a tremendous amount of energy in the balloon until
the calcified lesion breaks or cracks. That stored energy is then
released and may stress and injure the wall of the blood
vessel.
Electrohydraulic lithotripsy has been typically used for breaking
calcified deposits or "stones" in the urinary or biliary track.
Recent work by the assignee shows that lithotripsy electrodes may
similarly be useful for breaking calcified plaques in the wall of a
vascular structure. Shockwaves generated by lithotripsy electrodes
may be used to controllably fracture a calcified lesion to help
prevent sudden stress and injury to the vessel or valve wall when
it is dilated using a balloon. A method and system for treating
stenotic or calcified vessels is described in co-pending U.S.
application Ser. No. 12/482,995, filed Jun. 11, 2009. A method and
system for treating stenotic or calcified aortic valves is
described in co-pending U.S. application Ser. No. 13/534,658, filed
Jun. 27, 2012. As described in those applications, a balloon is
placed adjacent leaflets of a valve to be treated and is inflatable
with a liquid. Within the balloon is a shock wave generator that
produces shock waves that propagate through the liquid and impinge
upon the valve. The impinging shock waves soften, break and/or
loosen the calcified regions for removal or displacement to open
the valve or enlarge the valve opening. Additional improved
lithotripsy or shockwave electrodes that can readily access and
treat various locations in the vasculature for angioplasty and/or
valvuloplasty procedures may be desirable.
BRIEF SUMMARY
Described herein are low-profile electrodes for use with an
angioplasty shockwave catheter. A low-profile electrode assembly
may have an inner electrode, an insulating layer disposed over the
inner electrode such that an opening in the insulating layer is
aligned with the inner electrode, and an outer electrode disposed
over the insulating sheath such that an opening in the outer
electrode is coaxially aligned with the opening in the insulating
layer. This layered configuration allows for the generation of
shockwaves that initiate and/or propagate outward from a side of
the catheter. In some variations, the electrode assembly may have
at least a second inner electrode, and the insulating layer and
outer electrode may each have at least a second opening that are
coaxially aligned with the second inner electrode. An angioplasty
shockwave catheter may have a plurality of such low-profile
electrode assemblies along its length to break up calcified plaques
along a length of a vessel.
One variation of a device for generating shockwaves may comprise an
axially extending catheter, a balloon surrounding a portion of the
catheter, said balloon being fillable with a conductive fluid, an
insulating layer wrapped around a portion of the catheter within
the balloon, the insulating layer having a first aperture therein,
a first inner electrode carried within the catheter and aligned
with the first aperture of the insulating layer, and an outer
electrode mounted on the insulating layer and having a first
aperture coaxially aligned with the first aperture in the
insulating layer and arranged so that when the balloon is filled
with fluid and a voltage is applied across the electrodes, a first
shockwave will be initiated from a first side location of the
catheter. The insulating layer may be an insulating sheath and the
outer electrode may be in the form of a sheath that is
circumferentially mounted around the insulating sheath. The size of
the first aperture in the outer electrode may be larger than the
size of the first aperture in the insulating sheath. The device may
further comprise a first wire and a second wire, where the first
and second wires extend along the length of the catheter, and where
the first wire may be connected to the first inner electrode, and
the second wire may be connected to the outer electrode. In some
variations, the catheter may have first and second grooves that
extend along the length of the catheter, and the first wire is
slidably disposed within the first groove and the second wire is
slidably disposed within the second groove. For example, a length
of the first and second wires may be partially secured within the
first and second grooves. The first inner electrode and the outer
electrode may be crimped over an electrically conductive portion of
the first and second wires, respectively. In some variations, the
first inner electrode may be a hypotube that is crimped over the
first wire.
In some variations of a device for generating shockwave, the
insulating sheath may have a second aperture circumferentially
opposite the first aperture in the insulating sheath and the device
may further comprise a second inner electrode aligned with the
second aperture in the insulating sheath and the outer electrode
sheath may have a second aperture coaxially aligned with the second
aperture in the insulating sheath and arranged so that when the
balloon is filled with a fluid and a voltage is applied across the
second inner electrode and the outer electrode, a second shockwave
will be initiated from a second side location of the catheter that
is opposite to the first side location. In some variations, the
device may comprise a first wire, a second wire, and a third wire,
where the first, second and third wires that extend along the
length of the catheter, where the first wire is connected to the
first inner electrode, the second wire is connected to the outer
electrode, and the third wire is connected to the second inner
electrode. The catheter may have first, second and third grooves
that extend along the length of the catheter, and the first wire
may be slidably disposed within the first groove, the second wire
may be slidably disposed within the second groove, and the third
wire may be slidably disposed within the third groove. The first
inner electrode and the second inner electrode may be crimped over
an electrically conductive portion of the first and third wires,
respectively. The first inner electrode and the second inner
electrode may be first and second hypotubes that are each crimped
over the first and third wires, respectively. In some variations,
the surface of the first and second crimped hypotubes each
circumferentially spans a portion of the elongate member. For
example, the first and second crimped hypotubes may each
circumferentially span at least 1/6 of the way around the
circumference of the elongate member.
Optionally, the insulating sheath may have a third aperture
circumferentially 90 degrees from the first aperture in the
insulating sheath and may further comprise a third inner electrode
aligned with the third aperture in the insulating sheath. The outer
electrode sheath may have a third aperture coaxially aligned with
the third aperture in the insulating sheath and arranged so that
when the balloon is filled with a fluid and a voltage is applied
across the third inner electrode and the outer electrode, a third
shockwave will be initiated from a third side location that is 90
degrees offset from the first side location. In some variations,
the insulating sheath may have a fourth aperture circumferentially
opposite the third aperture in the insulating sheath and the device
may further comprise a fourth inner electrode aligned with the
fourth aperture in the insulating sheath. The outer electrode
sheath may have a fourth aperture coaxially aligned with the fourth
aperture in the insulating sheath and arranged so that when the
balloon is filled with a fluid and a voltage is applied across the
fourth inner electrode and the outer electrode, a fourth shockwave
will be initiated from a fourth side location that is opposite to
the third side location.
Another variation of a device for generating shockwaves may
comprise an axially extending catheter, a balloon surrounding a
portion of the catheter, the balloon being fillable with a
conductive fluid, a first inner electrode mounted on the side of
the catheter, an insulating layer having an aperture disposed over
the first inner electrode such that the aperture is coaxially
aligned with the first inner electrode, and an outer electrode
having an aperture disposed over insulating layer such that the
outer electrode aperture is coaxially aligned with the insulating
layer aperture. In some variations, the first inner electrode,
insulating layer and outer electrode do not protrude more than
0.015 inch from the outer surface of the catheter. The device may
further comprise a second inner electrode mounted on the side of
the catheter at a location that is circumferentially opposite to
the first inner electrode, where the insulating layer may have a
second aperture coaxially aligned with the second inner electrode
and the outer electrode may have a second aperture that is
coaxially aligned with the second aperture of the insulating
layer.
One variation of a system for generating shockwaves may comprise an
axially extending catheter, a balloon surrounding a portion of the
catheter, the balloon being fillable with a conductive fluid, a
first electrode assembly at a first location along the length of
the catheter, the first electrode assembly comprising a first inner
electrode, a second inner electrode, and an outer electrode and
configured to initiate shockwaves at two circumferentially opposite
locations, a second electrode assembly at a second location along
the length of the catheter, the second electrode assembly
comprising a first inner electrode, a second inner electrode, and
an outer electrode and configured to initiate shockwaves at two
circumferentially opposite locations, a third electrode assembly at
a third location along the length of the catheter, the third
electrode assembly comprising a first inner electrode, a second
inner electrode, and an outer electrode and configured to initiate
shockwaves at two circumferentially opposite locations, a fourth
electrode assembly at a fourth location along the length of the
catheter, the fourth electrode assembly comprising a first inner
electrode, a second inner electrode, and an outer electrode and
configured to initiate shockwaves at two circumferentially opposite
locations, a fifth electrode assembly at a fifth location along the
length of the catheter, the fifth electrode assembly comprising a
first inner electrode, a second inner electrode, and an outer
electrode and configured to initiate shockwaves at two
circumferentially opposite locations, and a voltage pulse
generator, where the channels of the voltage pulse generator are
connected to one or more of the electrode assemblies. In some
variations, the first inner electrode of the first electrode
assembly may be connected is a first output of the voltage pulse
generator, the second inner electrode of the first electrode
assembly may be connected to the first inner electrode of the
second electrode assembly, the first inner electrode of the third
electrode assembly may be connected to a second output of the
voltage pulse generator, the second inner electrode of the third
electrode assembly may be connected to a third output of the
voltage pulse generator, the first inner electrode of the fourth
electrode assembly may be connected to a fourth output of the
voltage pulse generator, the second inner electrode of the fourth
electrode assembly may be connected to the first inner electrode of
the fifth electrode assembly, and the second inner electrode of the
second electrode assembly, the outer electrode of the third
electrode assembly, and the second inner electrode of the fifth
electrode assembly may all be connected to a fifth output of the
voltage pulse generator.
Another variation of a device for generating shockwaves may
comprise an elongate member, a first electrode assembly located
along the side of the elongate member at a first longitudinal
location, where the first electrode assembly is configured to
initiate shockwaves at a first side location on the elongate
member, a second electrode assembly circumferentially opposite the
first electrode assembly, where the second electrode assembly is
configured to initiate shockwaves at a second side location that is
circumferentially opposite the first side location of the elongate
member, and a balloon surrounding a portion of the elongate member,
the balloon being fillable with a conductive fluid.
Another variation of a system for generating shockwaves may
comprise a high voltage pulse generator having a plurality of high
voltage output channels, a catheter, a plurality of shockwave
sources located along a length of the catheter, where the number of
high voltage output channels driving the plurality of shockwave
sources is less than the number of shockwave sources, and a balloon
surrounding the length of the catheter that has the shockwave
sources, the balloon being fillable with a conductive fluid.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 depicts a shockwave angioplasty device developed by the
assignee.
FIG. 2 is a cross-sectional view of a low-profile electrode.
FIGS. 3A-3E schematically depicts the assembly of another variation
of a low-profile electrode.
FIG. 4 depicts one variation of a shockwave angioplasty device.
FIG. 5A depicts another variation of a shockwave angioplasty
device.
FIGS. 5B and 5C are perspective views of a plurality of low-profile
shockwave electrode assemblies that may be used in a shockwave
angioplasty device.
FIGS. 5D and 5E are perspective and side views of a proximal hub of
a shockwave angioplasty device.
FIG. 5F is a side view of a high-voltage connector of a shockwave
angioplasty device.
FIG. 6A depicts a top view of one variation of a low-profile
shockwave electrode assembly and one variation of an inner
electrode.
FIGS. 6B and 6C depict various views of one variation of an outer
electrode sheath of a shockwave electrode assembly.
FIG. 6D depicts one variation of an insulating sheath of a
shockwave electrode assembly.
FIGS. 6E-6G depict other variations of an outer electrode sheath
and insulating sheath.
FIG. 6H depicts another variation of an inner electrode of a
shockwave electrode assembly.
FIGS. 7A-7D depict one method of assembling a low-profile shockwave
electrode assembly.
FIG. 8A depicts a side view of a catheter of a shockwave
device.
FIG. 8B is a cross-sectional view of the catheter of FIG. 8A.
FIG. 9 is a cross-sectional view depicting the connectivity between
a grooved wire and an outer electrode sheath of a shockwave
electrode assembly.
FIG. 10A schematically depicts a shockwave electrode assembly
having two inner electrodes that are in a direct connect
configuration.
FIGS. 10B-10D depict the connectivity between the inner electrodes
and outer electrodes to attain the configuration of FIG. 10A.
FIG. 11A schematically depicts a shockwave electrode assembly
configured in series.
FIGS. 11B-11D depict the connectivity between the inner electrodes
and outer electrodes to attain the configuration of FIG. 11A.
FIG. 12A schematically depicts two shockwave electrode assemblies
that are in a direct connect configuration.
FIGS. 12B and 12C depict the connectivity between the inner
electrodes and outer electrodes to attain the configuration of FIG.
12A.
FIG. 13A schematically depicts two shockwave electrode assemblies
configured in series.
FIGS. 13B-13D depict the connectivity between the inner electrodes
and outer electrodes to attain the configuration of FIG. 13A.
FIG. 14A schematically depicts the connectivity of five shockwave
electrode assemblies.
FIGS. 14B-14G depict the connectivity between the inner electrodes
and outer electrodes and intermediate nodes (e.g., a distal marker
band) to attain the configuration of FIG. 14A.
DETAILED DESCRIPTION
Described herein are devices and systems that comprise one or more
low-profile lithotripsy or shockwave electrodes that may be
suitable for use in angioplasty and/or valvuloplasty procedures.
Lithotripsy or shockwave electrodes may be sealed within an
angioplasty or valvuloplasty balloon that is inflated with a fluid
(e.g., saline and/or imaging contrast agent). A shockwave electrode
may be attached to a source of high voltage pulses, ranging from
100 to 10,000 volts for various pulse durations. This may generate
a gas bubble at the surface of the electrode causing a plasma arc
of electric current to traverse the bubble and create a rapidly
expanding and collapsing bubble, which in turn creates a mechanical
shockwave in the balloon. Shockwaves may be mechanically conducted
through the fluid and through the balloon to apply mechanical force
or pressure to break apart any calcified plaques on, or in, the
vasculature walls. The size, rate of expansion and collapse of the
bubble (and therefore, the magnitude, duration, and distribution of
the mechanical force) may vary based on the magnitude and duration
of the voltage pulse, as well as the distance between a shockwave
electrode and the return electrode. Shockwave electrodes may be
made of materials that can withstand high voltage levels and
intense mechanical forces (e.g., about 1000-2000 psi or 20-200 ATM
in a few microseconds) that are generated during use. For example,
shockwave electrodes may be made of stainless steel, tungsten,
nickel, iron, steel, and the like.
Traditional coaxial shockwave electrodes may be suitable for use in
an angioplasty or valvuloplasty balloon, however, when paired in
conjunction with a catheter having a guide wire lumen, the crossing
profile (i.e., cross-sectional area) may be too large to navigate
through and access certain regions of the vasculature. FIG. 1
depicting an example of a shockwave assembly 100 comprising a
balloon 106, a coaxial electrode 102 attached in parallel with a
catheter 104. For example, a coaxial electrode 102 may have a
cross-sectional diameter of about 0.025 inch to about 0.065 inch,
and a catheter 104 may have a cross-sectional diameter of about
0.035 inch, which would result in the assembly 100 having a total
cross-sectional diameter of at least about 0.06 inch. Such a large
crossing profile may limit the ability of the shockwave system to
treat tortuous vascular areas and also limit the number of patients
that may be treated. Described herein are low-profile shockwave
electrodes that may be located along the outer surface of an
elongate member (such as a catheter having a guide wire lumen) that
do not protrude more than 0.015 inch from the outer surface of the
elongate member. For example, the low-profile shockwave electrodes
described below may increase the crossing-profile of the elongate
member by only about 0.005 inch to about 0.015 inch, thereby
minimally affecting the ability of the elongate member to access
and treat target vascular tissue.
Also described herein are shockwave devices with a plurality of
electrodes along the side of an elongate member that are sealably
enclosed in a balloon (i.e., sealed in an enclosed balloon). Since
the magnitude, duration and distribution of the mechanical force
impinging on a portion of tissue depends at least in part on the
location and distance between the shockwave source and the tissue
portion, a shockwave device having multiple shockwave electrodes at
various locations along the length of the elongate member may help
to provide consistent or uniform mechanical force to a region of
tissue. The plurality of electrodes may be distributed across the
device (e.g., along a longitudinal length of the elongate member)
to minimize the distance between the shockwave source(s) and the
tissue location being treated. For example, a calcified region of a
vein or artery may extend over some longitudinal distance of the
vein or artery, and a point source shockwave electrode would not be
effective across the full extent of the calcified region because of
the varying distance from the shockwave source to the various
portions of the calcified region. Described herein are shockwave
devices that comprise a plurality of low-profile shockwave
electrodes located along a longitudinal length of an elongate
member to distribute shockwaves across a length of calcified
plaque. The low-profile shockwave electrodes may be located along
the circumference of an elongate member. The elongate member may
also be sized and shaped to distribute shockwave forces to a
non-linear anatomical region. For example, the elongate member may
be curved, having a radius of curvature that approximates the
radius of curvature of a valve (e.g., an aortic valve). A shockwave
device with a curved elongate member may be suitable for applying
shockwaves to break calcified plaques in the vicinity of a valve
and/or valve leaflets as part of a valvuloplasty procedure.
One variation of a low-profile shockwave electrode assembly may
comprise a first electrode, a second electrode stacked over the
first electrode, and an insulating layer between them. Stacking the
second electrode over the first electrode may form a layered
electrode assembly that may be formed on the side of a catheter
without substantially increasing the cross-sectional profile of the
catheter. A stacked or layered electrode assembly located on the
side of a catheter may also be able to generate shockwaves that
propagate from the side of the catheter without perpendicularly
protruding from the catheter (which would increase the
cross-sectional profile of the catheter). The insulating layer may
have a first opening and the second electrode may have a second
opening that is coaxially aligned with the first opening. Coaxial
alignment between the first opening in the insulating layer and the
second opening in the second electrode may comprise aligning the
center of each of the openings along the same axis. The opening in
the insulating layer and the opening in the second electrode may be
concentric, such that the center of the insulating layer opening is
aligned with the center of the second electrode opening. In some
variations, a shockwave device may comprise an elongate member
(such as a catheter) and a shockwave electrode assembly having a
first electrode that is substantially co-planar with the outer
surface of the elongate member. For example, the first electrode
may be a pronged electrode that is inserted into the elongate
member and connected to a high voltage source via wires within the
elongate member. Alternatively, the first electrode may be a
hypotube crimped to an electrically conductive portion of a wire,
where the wire is located within a longitudinal channel or groove
of the elongate member. The wire may have one or more electrically
insulated portions and one or more electrically conductive
portions, where the conductive portions may align with a first
opening of the insulating layer and a second opening of the second
electrode. The insulating layer may be a sheet or sheath that wraps
at least partially around the circumference of the elongate member
and overlaps the first electrode. The insulating layer may overlap
the first electrode such that the first electrode is electrically
isolated from the environment external to the elongate member but
for the opening in the insulating layer. The second electrode may
be a ring, sheet, or sheath having a second opening that stacks
and/or overlaps with the insulating layer such that the second
opening is coaxially aligned with the first opening of the
insulating layer. The second electrode may be circumferentially
wrapped over the insulating layer. Stacking the first electrode,
insulating layer, and second electrode along the outer surface of
the elongate member may allow for a shockwave electrode assembly to
have a low profile with respect to the elongate member, and
coaxially aligning the opening of the insulating layer with the
opening of the second electrode may allow for the generation of
shockwaves that propagate from the side of the elongate member.
One example of a low-profile shockwave electrode assembly is
depicted in FIG. 2. FIG. 2 depicts a cut away perspective view of a
low-profile coaxial shockwave electrode assembly 200 that may be
located on an elongate member 20 (e.g., a catheter) and enclosed in
a balloon (e.g., an angioplasty or valvuloplasty balloon). The
electrode assembly 200 may comprise a first electrode 1, an
insulating layer 2 overlaying the first electrode, and a second
electrode 3. The first electrode 1 may be a positive electrode and
the second electrode 3 may be a negative electrode (or vice versa).
The elongate member 20 may have a guide wire lumen extending along
a length of its longitudinal axis. The first electrode 1 may have a
thickness from about 0.001 inch to about 0.01 inch, e.g., 0.002
inch, and may be attached along the outer surface of the elongate
member 20. The insulating layer 2 may be made of any material with
a high breakdown voltage, such as Kapton, ceramic, polyimide or
Teflon. The insulating layer 2 may be about 0.001 inch to about
0.006 inch, e.g., 0.0015 inch, 0.0025 inch, and may have an opening
7 that is aligned over the first electrode 1. Although the second
electrode 3 is depicted as having a ring shape, it should be
understood that the second electrode may be a planar sheet or
layer. The second electrode 3 may have a central opening 8 and
stacked over the insulating layer 2 such that the second electrode
opening 8 is coaxially aligned with the insulating layer opening 7.
The openings 7, 8 may be in the shape of a circle, oval, ellipse,
rectangular, or any desired shape. The second electrode 3 may have
a thickness from about 0.001 inch to about 0.015 inch, e.g., 0.0025
inch, 0.004 inch. The total thickness of the shockwave electrode
assembly 200 may be from about 0.002 inch to about 0.03 inch e.g.,
0.005 inch, 0.007 inch, 0.008 inch. Layering and stacking the first
electrode, insulating layer and second electrode as depicted in
FIG. 2 maintains a substantially flat profile against the outer
surface of the elongate member, while maintaining a coaxial
electrode configuration for efficient shockwave production. That
is, such a configuration may be electrically similar to a
traditional coaxial lithotripsy assembly having an inner electrode
and an outer electrode surrounding the inner electrode, but without
substantially increasing the crossing profile of the elongate
member. For example, electrode assembly 200 may have a small enough
thickness such that it does not extend more than 0.015 inch from
the outer diameter of the elongate member 20. By applying a high
voltage pulse between first electrode 1 and second electrode 3 in a
fluid filled balloon that encloses the shockwave electrode
assembly, an electrohydraulic shockwave can be generated that
propagates outward from the side of the elongate member 20. The gap
that the current must cross may be at least partially determined by
the size and location of the opening 7 in the insulating layer 2
and the size and location of the opening 8 in the second electrode
3. For example, the opening 7 in the insulating layer may be larger
than the opening 8 in the second electrode. The opening 7 in the
insulating layer may have a diameter from about 0.004 inch to about
0.010 inch, e.g., about 0.008 inch, and the opening 8 in the second
electrode may have a diameter from about 0.010 inch to about 0.02
inch, e.g., about 0.012 inch, 0.016 inch, 0.018 inch. The ratio of
the diameters between the openings 7, 8 may be varied to adjust the
force and duration of the generated shockwave. In some variations,
the ratio between the diameter of the opening 7 in the insulating
layer and the diameter of the opening 8 in the second electrode may
be about 0.5, e.g., 0.56. In some variations, the gap between the
openings 7, 8 may be related to the thickness of the insulating
layer. For example, the gap between the openings may be
0.5*(diameter of opening 8-diameter of opening 7)+thickness of the
insulating layer 2. The desired gap size may vary according to the
magnitude of the high voltage pulse applied to the first electrode
1. For example, a gap of about 0.004 inch to about 0.006 inch may
be effective for shockwave generation using voltage pulses of about
3,000 V.
Another variation of a layered or stacked shockwave electrode
assembly may comprise an inner electrode located along or recessed
within the outer surface of an elongate member, an insulating layer
or sheath that circumferentially wraps the elongate member, and an
outer electrode that circumferentially wraps around the elongate
member and over the insulating sheath. For example, the first
electrode may be pressed into the outer surface of the elongate
member, and attached to the elongate member by an adhesive (e.g., a
conductive adhesive such as conductive epoxy), crimping, welding,
and/or pinching. FIGS. 3A-3E depict one variation of a low profile
shockwave device 300 comprising an elongate member 320, an inner
electrode 306 pressed into and/or recessed within the outer wall of
the elongate member 320, an insulating layer 302 disposed over the
first electrode 306 such that a first opening 307a in the
insulating layer is located over the first electrode, and an outer
electrode 308 disposed over the insulating layer 302 such that a
first opening 317a in the outer electrode is coaxially aligned with
the first opening 307a in the insulating layer. The insulating
layer 302 and the outer electrode 308 may each be in the form of a
sheath or band, where the insulating sheath may be placed and/or
wrapped over the inner electrode and the second electrode sheath
may be placed and/or wrapped over the insulating sheath such that
the openings in the insulating sheath and outer electrode sheath
are coaxially aligned. In some variations, the openings in the
insulating sheath and outer electrode sheath are circular and are
coaxially aligned such that the centers of the openings are aligned
along the same axis and/or concentric. The insulating layer, outer
electrode, and second inner electrode may be stacked such that the
center of the first opening in the insulating layer, the center of
the first opening in the outer electrode, and the first inner
electrode are aligned on the same axis. The elongate member may
comprise a longitudinal lumen 304 along at least a portion of its
length, where the lumen 304 may be configured for passing various
instruments and/or a guide wire therethrough. In some variations,
the elongate member may be a catheter with a guide wire lumen. The
elongate member may also comprise one or more conductors that may
extend along the length of the elongate member to connect the inner
and/or outer electrode to a high voltage pulse generator. For
example, the elongate member may comprise a first wire 305 and a
second wire 310 that may be extruded within the walls of the
elongate member 320, as depicted in FIG. 3B. Alternatively, the
wires could be located in additional longitudinal lumens of the
elongate member and/or be located in longitudinal grooves along the
outer surface of the elongate member. The wires 305 and 310 may be
surrounded by the insulating material of the elongate member and
are therefore electrically insulated from each other. Alternatively
or additionally, the wires may each have insulating sleeves that
wrap around them. The conductive portion of the wires may be
exposed at certain locations along its length to contact the inner
and outer electrodes. The wires may contact the inner and outer
electrodes by soldering, crimping, stapling, pinching, welding,
conductive adhesive (e.g., using conductive epoxy), and the like,
as further described below. In some variations, the inner electrode
may be a hypotube that is crimped to the wire. The connectivity
between the conductors and the inner and outer electrodes may be
such that the inner electrode is the positive terminal and the
outer electrode is the negative terminal (or vice versa). Such a
configuration may allow a shockwave generated between the inner and
outer electrodes to propagate outward from the side of the elongate
member.
Optionally, a shockwave device may have more than one low-profile
electrode assembly along the side of the elongate member. In some
variations, a first electrode assembly may be located along a side
of the elongate member while a second electrode assembly may be
located on the opposite side of the elongate member (i.e., 180
degrees from each other). For example and as depicted in FIGS.
3A-3E, the shockwave device 300 may comprise a second inner
electrode 330 pressed into and/or recessed within the outer wall of
the elongate member 320, opposite the first electrode 306. The
elongate member may further comprise a third wire 309 to connect
the second inner electrode 330 to a high voltage pulse generator.
The insulating layer 302 and the outer electrode may each have an
additional opening 307b, 317b (respectively) that are coaxially
aligned with each other and with the second inner electrode 330.
The insulating layer, outer electrode, and second inner electrode
may be stacked such that the center of the second opening in the
insulating layer, the center of the second opening in the outer
electrode, and the second inner electrode are aligned on the same
axis. The first electrode assembly 340 may comprise the first inner
electrode 306, the insulating layer 302 with the first opening 307a
aligned over the first inner electrode, and the outer electrode 308
with the first opening 317a coaxially aligned with the first
opening 307a of the insulating layer. The second electrode assembly
350 may comprise the second inner electrode 330, the insulating
layer 302 with the second opening 307b aligned over the second
inner electrode, and the outer electrode 308 with the second
opening 317b coaxially aligned with the second opening 307b of the
insulating layer. By sharing the same insulating layer 320, the
first coaxial electrode assembly and the second coaxial electrode
assembly may be located at the same longitudinal position along the
elongate member. A shockwave device comprising two or more
low-profile electrode assemblies located at the same longitudinal
position may allow for shockwaves to propagate outward from the
elongate member with various angular spread (e.g., up to 360 degree
angular spread). For example, a first shockwave generated by the
first electrode assembly may propagate outward with an angular
spread of about 180 degrees around the elongate member and a second
shockwave generated by the second electrode assembly located
opposite the first electrode assembly (e.g., 180 degrees from the
first electrode assembly) may propagate outward with an angular
spread of about 180 degrees around the other side of elongate
member, for a cumulative spread of 360 degrees around the elongate
member. In other variations, a shockwave device may comprise three
or more electrode assemblies, where the three or more electrode
assemblies may also be located at the same longitudinal location,
but located at different circumferential locations. For example,
there may be an additional third electrode and fourth inner
electrode around the circumference of the elongate member. The
insulating layer may have additional openings aligned over the
additional third and fourth inner electrodes, and the outer
electrode may have additional openings aligned over the openings of
the insulating layer. The third and fourth electrode assemblies
formed by the third and fourth inner electrodes and the additional
openings in the insulating layer and outer electrode may allow for
the generation of four shockwaves from the same longitudinal
location along the elongate member. For example, the first, second,
third and fourth electrode assemblies may be at the same position
along the length of the elongate member, but be circumferentially
distributed around the elongate member 90 degrees apart from each
other (i.e., the first electrode assembly may be at position 0
degrees, the second electrode assembly may be a position 180
degrees, the third electrode assembly may be at position 90
degrees, and the fourth electrode assembly may be at 270 degrees).
This may give rise to four shockwaves that propagate outward, each
fanning out with an angular spread of about 90 degrees. The
assembly of a shockwave device with two low-profile electrode
assemblies at the same position along the length of the elongate
member is described below, but it should be understood that similar
methods may be used to assemble shockwave devices with three or
more low-profile electrode assemblies at the same longitudinal
position along the length of the elongate member.
As depicted in FIG. 3B, the first inner and second inner electrodes
306, 330 may be pronged electrodes 306a, 330a and may be shaped to
be pressed into the wall of the insulating material of the elongate
member. Electrical contact between the first inner and second inner
electrodes and the first and third wires may be attained via finger
extensions of the pronged electrodes. The pronged electrodes 306a,
330a may have finger extensions 306b, 330b that pinch the first and
third wires 305, 309 (respectively) in the wedge of the fingers.
The pronged electrodes may also be electrically connected to the
wires by any suitable method, for example, soldering, crimping,
welding, conductive adhesives (e.g., using conductive epoxies),
pressure fit, interference fit, etc. FIG. 3C depicts the first
inner and second inner electrode pressed into the side of the
elongate member such that the first inner electrode and second
inner electrode make electrical contact with the first and third
wires within the elongate member. The pronged electrodes 306a, 330a
may form the first layer of a stacked low-profile shockwave
electrode assembly (e.g., similar to the layered or stacked
configuration of the electrode assembly depicted in FIG. 2). The
pronged electrodes may comprise tungsten, stainless steel, platinum
iridium, nickel, iron, steel, and/or other electrically conductive
material.
The insulating sheath 302 may circumferentially wrap around the
elongate member 320 such that it overlaps with and overlays the
first inner electrode and second inner electrode, as depicted in
FIG. 3D. The insulating sheath 302 may overlap and stack on top of
the first inner electrode and second inner electrode 306 and 330
such that the first opening 307a is coaxially aligned with the
first inner electrode and the second opening 307b is aligned with
the second inner electrode. The insulating sheath 302 may be made
of any material that has a high breakdown voltage, such as Kapton,
polyimide, ceramic, Teflon, or any combination of such materials.
The insulating sheath 302 may be placed over the elongate member by
sliding it from one end of the elongate member to the desired
location. The insulating sheath 302 may be secured in the desired
location by friction fit, adhesive, welding, crimping, or any other
suitable method.
The outer electrode 308 may be a sheath or band that may be
configured to stack on top of and/or wrap over the insulating layer
302, as shown in FIG. 3E. The outer electrode 308 may have an
extension 319 with pointed fingers 318 configured to penetrate the
elongate member to contact the second wire 310 (e.g., by crimping
the fingers 318 so that the fingers are pressed into and on the
wire 310). The outer electrode 308 may be a metallic sheath or band
that may wrap or enclose the elongate member. The outer electrode
308 may be positioned such that the first opening 317a is coaxially
aligned with the first opening 307a of the insulating sheath 302
and the second opening 317b is coaxially aligned with the second
opening 307b of the insulating sheath. In some variations, the
outer electrode 308 may be slid over one end of the elongate member
and moved longitudinally into the desired position, after which it
may be secured by friction fit, conductive adhesive (e.g., using
conductive epoxy), welding, soldering, crimping, or any other
suitable method. The outer electrode 308 may be made of copper,
stainless steel, platinum/iridium or other electrically conductive
materials.
As described above, the first inner electrode may be connected to
the first wire 305 and the second inner electrode may be connected
to the third wire 309. In some variations, the high voltage pulse
generator may drive the first wire 305 and third wire 309 together
or independently. For example, the pulse generator may apply
voltage pulses simultaneously to both wires, and/or may apply
voltage pulses sequentially (e.g., a voltage pulse is applied to
the first wire without applying a pulse to the third wire, or vice
versa). The voltage pulses applied to the third wire may be delayed
with respect to the voltage pulses applied to the first wire. In
some variations, a multiplexor may be used with the high voltage
pulse generator to control application of pulses between the first
and third wires. This may allow shockwaves with different
frequency, magnitude, and timing to be generated on either side of
the elongate member. For example, in some procedures it may be
desirable to apply shockwaves on one side of the elongate member
but not on the other side (e.g., in an angioplasty procedure where
there is a calcified lesion in one portion of the vessel but not in
other portions of the vessel). The first, second, and third wires
may be directly connected to a high voltage pulse generator, or may
first connect to a connector that is then plugged into the high
voltage pulse generator.
One example of a shockwave device comprising one or more of the
low-profile electrode assemblies described above is depicted in
FIG. 4. The shockwave device depicted there may be suitable for use
in an angioplasty or valvuloplasty procedure. Shockwave device 400
may comprise a catheter 402, a first low-profile coaxial electrode
assembly 404, a second low-profile coaxial electrode assembly 406
(not visible in this view), and a balloon 408 enclosing the portion
of the elongate member where the first and second electrode
assemblies are located. The balloon may be made of an electrically
insulating material that may be rigid (e.g., PET, etc.), semi-rigid
(e.g., PBAX, nylon, PEBA, polyethylene, etc.), or flexible (e.g.,
polyurethane, silicone, etc.). The first and second electrode
assemblies may be located radially across from each other such that
the shockwaves they each generate propagate in opposite directions.
The shockwaves generated by each of the electrode assemblies may
propagate outward, with an angular spread of 180 degrees. The inner
electrodes of each of the electrode assemblies may be connected to
conductors within the catheter 402, which may be connect to a high
voltage pulse generator. In some variations, the high voltage pulse
generator may be a 2 kV to 6 kV, e.g., 3 kV, pulsed power supply.
The inner electrode of the first electrode assembly may be
connected to a first positive lead of the pulse generator while the
inner electrode of the second electrode assembly may be connected
to a second positive lead of the pulse generator. The outer
electrode may be connected to a negative lead of the pulse
generator, or to ground. The first and second positive leads of the
pulse generator may be pulsed simultaneously or separately, and may
be controlled together or separately controlled (e.g. using a
multiplexor), as described previously.
Additional low-profile shockwave electrode assemblies may
alternatively or additionally be located along a plurality of
locations along the length of the elongate member. For example, the
low-profile coaxial shockwave electrode assemblies described above
may be linearly arranged along the longitudinal length of the
elongate member. Additional variations of shockwave devices with a
plurality of electrode assemblies are described below.
One example of a shockwave device which may be configured for
shockwave angioplasty is depicted in FIG. 5A-5F. Shockwave
angioplasty system 520 may comprise a catheter 522, a proximal hub
524, one or more shockwave electrode assemblies 526 at a distal
portion of the catheter, a high-voltage connector 530 for
connecting the shockwave assemblies to a pulse generator, and an
angioplasty balloon 528 configured to be inflated with a fluid. A
proximal portion of the wires from the shockwave assemblies may
form a cable 576 that may be enclosed in a jacket. The cable may
extend from a lumen of the proximal hub 524 and connect to the
high-voltage connector 530. Pins within the high-voltage connector
may connect each of the wires from the shockwave assemblies to the
appropriate channel on a high voltage pulse generator. Optionally,
the system 520 may additional comprise a strain relief tube 532
connected to the hub 524. The catheter 522 may have a guide wire
lumen therethrough. There may be any number of shockwave electrode
assemblies located at the distal end of the catheter and enclosed
by the balloon. For example, there may be one shockwave electrode,
two shockwave electrode assemblies, four shockwave electrode
assemblies, five shockwave electrode assemblies or more. FIGS. 5B
and 5C depict the distal portions of shockwave devices with two
electrode assemblies and five electrode assemblies. FIG. 5B depicts
one variation of a shockwave device 500 comprising an elongate
member 502, a first electrode assembly 504 at a first location
along the length of the elongate member, a second electrode
assembly 506 at a second location along the length of the elongate
member, and a balloon 508 configured to be filled with a fluid to
sealably enclose the first and second electrode assemblies. The
balloon 508 may be made of an electrically insulating material that
may be rigid (e.g., PET, etc.), semi-rigid (e.g., PBAX, nylon,
PEBA, polyethylene, etc.), or flexible (e.g., polyurethane,
silicone, etc.). The first and second electrode assemblies may be
spaced apart along the length of the elongate member, and may be
from about 3 mm to about 20 mm apart from each other, e.g., about 5
mm, 7 mm, 10 mm. The length of the balloon may vary depending on
the number of electrode assemblies and the spacing between each of
the electrode assemblies. For example, a balloon for a shockwave
device with two electrode assemblies spaced about 7 mm apart (e.g.,
6.7 mm) may have a length of about 20 mm. A balloon for a shockwave
device with five electrode assemblies spaced about 10 mm apart may
have a length of about 60 mm. The electrode assemblies 504, 506
each comprise two inner electrodes that are positioned
circumferentially opposite each other, an insulating sheath with
two openings aligned over the two inner electrodes, and an outer
electrode sheath with two openings that are coaxially aligned with
the two openings of the insulating sheath. Each of the electrode
assemblies 504, 506 are configured to generate a pair of directed
shockwaves, where the shockwaves resulting from a high voltage
pulse to the first inner electrode propagate in a direction that is
opposite to the direction of the shockwaves resulting from a high
voltage pulse to the second inner electrode. The electrode
assemblies 504, 506 may generate shockwaves that propagate outward
from different locations around the circumference of elongate
member 502. For example, the electrode assembly 504 may generate
shockwaves that propagate from the left and right longitudinal side
of the elongate member, while the electrode assembly 506 may
generate shockwaves that propagate from the top and bottom
longitudinal side of the elongate member. In some variations, the
electrode assembly 504 may generate a pair of shockwaves that
propagate outward from positions at 0 degrees and 180 degrees
around the circumference of the elongate member 502, while the
electrode assembly 506 may generate a pair of shockwaves that
propagate outward from positions at 60 degrees and 240 degrees
around the circumference of the elongate member. In still other
variations, electrode assemblies 504, 506 may each generate a pair
of shockwaves that propagate outward at the same locations around
the circumference of the elongate member, but from different
locations along the length of the elongate member. Optionally, a
radiopaque marker bands may be provided along the length of the
elongate member to allow a practitioner to identify the location
and/or orientation of the shockwave device as it is inserted
through the vasculature of a patient. For example, there may be a
first marker band proximal to the first electrode assembly and a
second marker band distal to the second electrode assembly. In some
variations, one or more marker bands may be located proximal to the
proximal-most electrode assembly, and/or distal to the distal-most
electrode assembly, and/or in the center of the elongate member
and/or any other location along the length of the elongate
member.
FIG. 5C depicts another shockwave device 550 comprising an elongate
member 552, a first electrode assembly 554, a second electrode
assembly 556, a third electrode assembly 558, a fourth electrode
assembly 560, a fifth electrode assembly 562, and a balloon 564
configured to be filled with a fluid to sealably enclose the first,
second, third, fourth, and fifth electrode assemblies. The balloon
564 may be made of an electrically insulating material that may be
rigid (e.g., PET, etc.), semi-rigid (e.g., PBAX, nylon, PEBA,
polyethylene, etc.), or flexible (e.g., polyurethane, silicone,
etc.). The electrode assemblies of shockwave device 550 may be
similar to the ones described in FIG. 5B, and/or may be similar to
any of the electrodes described herein. The elongate member may be
a catheter with a longitudinal guide wire lumen. Each of the
electrode assemblies are configured to generate a pair of
shockwaves that propagate in two opposite directions from the side
of the elongate member. The electrode assemblies of FIG. 5C may be
configured to generate shockwaves that propagate outward from
different locations around the circumference of elongate member, as
described above for FIG. 5B. Although the figures herein may depict
shockwave devices with two or five electrode assemblies, it should
be understood that a shockwave device may have any number of
electrode assemblies, for example, 3, 4, 6, 7, 8, 9, 10, 15, 20,
etc. The electrode assemblies may be spaced apart along the length
of the elongate member, and may be from about 3 mm to about 10 mm
apart from each other, e.g., about 5 mm, 8 mm, 10 mm, etc.
depending on the number of electrode assemblies and the length of
the elongate member that is enclosed within the balloon. Shockwave
devices with a plurality of electrode assemblies distributed along
the length of a catheter may be suitable for use in angioplasty
procedures to break up calcified plaques that may be located along
a length of a vessel. Shockwave devices with a plurality of
electrode assemblies along the length of a curved elongate member
may be suitable for use in valvuloplasty procedures to break up
calcified plaques that may be located around the circumference of a
valve (e.g., at or around the leaflets of a valve). The electrode
assemblies of FIGS. 5A-5C may be similar to the electrode
assemblies described above and depicted in FIGS. 3A-3E, and/or may
be any of the electrode assemblies described below.
FIGS. 5D and 5E are detailed views of the proximal hub 524. As
shown there, proximal hub 524 may comprise a central shaft 542, a
first side shaft 540 and a second side shaft 544. The first and
second side shafts are attached to either side of the central shaft
542. The central shaft 542 may have a proximal opening 548 that is
connected to an inner lumen 543 that extends through the length of
the central shaft and terminates at a distal opening 546 that is
configured to interface with the strain relief and the catheter
522. The inner lumen 543 may be in communication and/or continuous
with the guide wire lumen of the catheter 522. The first side shaft
540 may have an opening 547 that is connected to an inner lumen
541, which is in communication and/or continuous with the inner
lumen 543 of the central shaft 542. The second side shaft 544 may
have an opening 549 that is connected to an inner lumen 545. The
inner lumen 545 of the second side shaft 544 may not be connected
to the central inner lumen 543. The inner lumens 541, 543, 545 may
each have a wider proximal region and a narrower distal region,
which may act as a stop for the devices inserted into the shafts.
The central shaft 548 and its inner lumen 543 may function as a
port for the insertion of a guidewire and/or to deliver an imaging
contrast agent to the distal end of the catheter 522. The first
side shaft 540 and inner lumen 541 may function as an inflation
port for saline and/or imaging contrast agent. The second side
shaft 549 and inner lumen 545 may function as a port through which
the cable 576 may extend and connect to the high voltage connector
530 to electrically connect a high voltage pulse generator to the
shockwave electrode assemblies at the distal end of the catheter.
The cable 576 may be bonded to the connector 530 and/or the hub. In
some variations, the proximal hub 524 may be made of injection
molded polycarbonate. The length L1 of the central shaft 542 may be
from about 2 inches to about 4 inches, e.g., about 2.3 inches or
2.317 inches, while the length L2 of the side shafts 540, 544 may
be from about 1 inch to about 2 inches, e.g., about 1.4 inches or
1.378 inches. The diameter D1 of the narrowest portion of the
central inner lumen D1 may be from about 0.05 inch to about 0.1
inch, e.g., about 0.08 inch to about 0.082 inch.
FIG. 5F is a detailed view of the high voltage connector 530 that
may be inserted through at least one of the ports of the proximal
hub, and configured to connect the shockwave electrode assemblies
526 to a high voltage pulse generator. The high voltage connector
530 may have a proximal port 570 that is configured to connect with
a port of a high voltage pulse generator, a first shaft region 572,
and a second shaft region 574 that is narrower than the first shaft
region 572 that may connect to cable 576. The first shaft region
572 may have a diameter D3 that is greater than the diameter of the
narrower portion of an inner lumen of the proximal hub, but smaller
than the diameter of the wider portion of the inner lumen. The
second shaft region 574 distal to the first shaft region may be
configured for strain relief. For example, the cable 576 may
provide connections for both the high voltage pulse(s) and the
return path between the voltage pulse generator and the electrode
assemblies. In some variations, the cable may provide one or more
high voltage supply connections to the electrode assemblies, with
one or more return connections. For example, the cable may provide
for a single high voltage supply connection and a single return
connection to the electrode assemblies. Alternatively, the cable
may provide for a plurality of high voltage supply connections
(e.g., four) and one or more return connections to the electrode
assemblies. The proximal port 570 may have a length L3 from about
1.5 inches to about 3 inches, e.g., about 2 inches or 2.059 inches,
and a diameter D2 from about 0.2 inch to about 1 inch, e.g., about
0.7 inch or 0.72 inch. The diameter D3 of the first shaft region
572 may be from about 0.05 in to about 0.2 inch, e.g., about 0.1
inch or 0.112 inch.
FIG. 6A depicts another variation of a low-profile coaxial
shockwave electrode assembly that may be used in any of the
shockwave devices described herein. The electrode assembly 600 may
comprise a first inner electrode 604, an insulating layer or sheath
606 disposed over the first inner electrode and circumferentially
wrapped around an elongate member 602 (e.g., a catheter with a
guidewire lumen), and an outer electrode sheath 608 disposed over
the insulating sheath. While the insulating sheath is depicted as
fully circumscribing the elongate member, it should be understood
that in other variations, an insulating layer may not fully
circumscribe the elongate member, and may instead be disposed over
certain portions of the elongate member. The insulating sheath 606
may have a first opening 607a that is coaxially aligned over the
first inner electrode 604, and the outer electrode sheath 608 may
have a first opening 609a that is coaxially aligned over the first
opening of the insulating sheath. The electrode assembly 600 may
also comprise a second inner electrode that is circumferentially
opposite (or otherwise displaced from) the first inner electrode
(and therefore not depicted in the view shown in FIG. 6A). The
insulating sheath may have a second opening 607b that is coaxially
aligned over the second inner electrode, and the outer electrode
sheath may have a second opening 609b that is coaxially aligned
over the second opening of the insulating sheath. The first inner
electrode coaxial with the first openings in the insulating sheath
and the outer electrode sheath may generate a first shockwave that
propagates outwards in a first direction and the second inner
electrode coaxial with the second openings in the insulating sheath
and the outer electrode sheath may generate a second shockwave that
propagates outwards in a second direction that is opposite to the
first direction. The diameter of the openings in the outer
electrode sheath may be larger than the diameter of the openings in
the insulating sheath. The size of and ratio between the diameter
of the openings in the outer electrode and the openings in the
insulating sheath may be adjusted to attain the desired shockwave
characteristics, as described above. The edges of the openings in
any of the outer electrodes described herein may be
electropolished. Alternatively, some variations of an electrode
assembly may not have an insulating sheath or layer disposed over
the elongate member, but may instead comprise an inner electrode
having an insulating coating directly applied over the inner
electrode (e.g., disposed over the crimped hypotube of the inner
electrode). The insulating coating may cover the inner electrode
such that a region of the conductive portion of the inner electrode
is exposed, while the rest of the inner electrode is covered by the
coating. The opening in the outer electrode sheath may be coaxially
aligned with the exposed region of the inner electrode. The
thickness and/or material of the insulating coating may be varied
depending on the magnitude of the voltage to be applied on the
electrode. Examples of insulating coatings may be Teflon,
polyimide, etc. Using an insulating coating on the inner electrode
instead of an insulating layer disposed over the elongate body may
further reduce the crossing profile of the electrode assembly, and
may allow for more bending or a tighter turning radius than an
electrode assembly having an insulating sheath.
The inner electrodes and the outer electrode may each be connected
to a high voltage pulse generator via a plurality of wires 610 that
may be located within a plurality of longitudinal grooves 601 along
the outer surface of the elongate member 602 (e.g., a catheter
having a guidewire lumen) of the shockwave device. The wires may be
electrically insulated along its length (e.g., by an insulating
coating or sheath made of, for example, polyimide, PEBA, PET, FEP,
PTFE, etc.) except for one or more regions where the electrically
conductive core of the wire is exposed to contact a portion of the
inner and/or outer electrode. For example, the insulating coating
or sheath at the distal tip of the wire may be stripped to expose
the conductive portion. The wires may be made of any conductive
material, for example, free oxygen copper or copper or silver. The
inner electrode 604 may be a hypotube that is crimped over the
distal tip of the wire 610, where the wire 610 is enclosed within
one of a plurality of grooves 601 of the elongate member. The
hypotube may be made of stainless steel, tungsten, a
platinum-iridium alloy, or any other material with similar
hardness. In variations of an electrode assembly without an
insulating layer disposed over the elongate member, a portion of
the hypotube may be coated with an insulating material as described
above. Each groove of the elongate member may partially enclose a
single wire. For example, the wire 610 may be half enclosed within
a groove of the elongate member, such that half of the wire is
recessed or embedded within the groove and half of the wire
protrudes outside of the groove. The wire 610 may be slidably
disposed within the groove. As the elongate member is curved or
bent (e.g., during an angioplasty procedure where the elongate
member is a catheter that is advanced through a patient's
vasculature), the wire may slide within the groove to accommodate
changes in the radius of curvature as the elongate member bends,
thereby minimally interfering with the flexibility of the elongate
member. Optionally, one or more shrink tubes may be provided to
retain the wire within the groove without impinging on its ability
to move and shift as the elongate member bends or curves. For
example, one or more bands of shrink tubes may be located
circumferentially around the distal portion of the elongate member.
Alternatively or additionally or optionally, dots of epoxy may be
applied along a distal length of the wires to partially secure or
retain the wires within the grooves while still maintaining the
ability of the wires to partially move and shift as the elongate
member bends or curves. In some variations, the wires may slide
within the grooves without any retaining elements. Additional
details regarding the longitudinal grooves of the elongate member
are provided below.
FIGS. 6B and 6C depict perspective and side view of the outer
electrode sheath 608. In some variations, the outer electrode may
be a radiopaque marker band (e.g., marker band used in angioplasty
procedures). As depicted there, the first opening 609a may be
located directly across from the second opening 609b. FIG. 6D
depicts a perspective view of the insulating sheath 606 having a
first opening 607a and a second opening 607b located directed
across from the first opening 607a. As described above, each of
these openings may be coaxially aligned with the openings of the
insulating sheath 606 and first and second inner electrodes to form
two shockwave sources capable of generating two shockwaves that
propagate outward from the side of the elongate member in two
opposite directions. FIGS. 6E and 6F depict another variation of an
outer electrode sheath 620 that comprises two openings 622a, 622b
that are circumferentially across each other, but laterally offset.
The diameter of each of the openings 622a, 622b may be from about
0.010 inch to about 0.024 inch, e.g., about 0.014 inch. FIG. 6G
depicts a variation of an insulating sheath 630 that comprises two
openings 632a, 632b that are circumferentially across each other,
but laterally offset. The diameter of each of the openings 632a,
632b may be from about 0.004 inch to about 0.01 inch, e.g., about
0.008 inch. The size and ratio of the openings in the insulating
sheath and the outer electrode may be similar to those described
previously (see FIG. 2 and accompanying description). The openings
622a, 622b of the outer electrode sheath may be coaxially aligned
with the openings 632a, 632b of the insulating sheath 630,
respectively. The outer electrode sheath 620 and the insulating
sheath 630 may be used with a pair of inner electrodes that are
similarly circumferentially across each other, but laterally offset
such that the two inner electrodes are each coaxially aligned with
the each of the openings in the insulating sheath and the outer
electrode sheath. This may functionally create two shockwave
sources configured to generate two shockwaves that propagate
outward in two directions that are opposite each other but
laterally offset.
In the variations of the shockwave electrode assemblies described
above, the inner electrode is retained within a longitudinal groove
of a catheter, and the openings of an insulating sheath and outer
electrode are coaxially aligned with the inner electrode. As a
result, the circumferential position of the openings in the
insulating sheath and the outer electrode (and therefore, the
circumferential position of a shockwave source) may be constrained
by the circumferential position of the longitudinal groove that
retains the inner electrode. In some variations, it may be
desirable to position a shockwave source at a circumferential
position around the elongate member that is different from the
circumferential position of the groove that retains the inner
electrode. That is, the location of the shockwave source as defined
by the circumferential location of the openings in the insulating
sheath and outer electrode sheath may be offset with respect to the
groove. A cross-section of such shockwave electrode assembly is
depicted in FIG. 6H. Depicted there is a catheter 640 with a
central guide wire lumen 641 and first and second grooves 642a,
642b that are located circumferentially opposite each other (e.g.,
180 degrees around the catheter). First and second wires 644a, 644b
are retained within the grooves 642a, 642b and are connected to
first and second inner electrodes 646a, 646b. The first and section
wire 644a, 644b and grooves 642a, 642b are aligned along axis 654.
However, it may be desirable to have a shockwave source be located
at a location that is offset from a first axis 654, for example at
a location that is radially offset by angle A1 (which may be from
about 1 degree to about 179 degrees). To form a shockwave electrode
assembly that is offset by angle A1 from the first axis 654, the
first and second inner electrodes 646a, 646b may each be a hypotube
that is asymmetrically crimped so that a length of the hypotube
circumferentially spans a portion of the catheter. For example, in
the variation shown in FIG. 6H, the inner electrodes 646a, 646b may
span at least an angle A1 along the circumference of the catheter
640. The first and second openings 647a, 647b of the insulating
sheath 648 may be coaxially aligned over the first and second inner
electrodes at the radially offset location, and the first and
second openings 651a, 651b of the outer electrode 650 may be
coaxially aligned over first and second openings 647a, 647b of the
insulating sheath 648. In other words, the first and second
openings 647a, 647b of the insulating sheath 648, the first and
second openings 651a, 651b of the outer electrode 650, and a
portion of the first and second inner electrodes 646a, 646b may be
coaxially aligned along a second axis 652 that is offset by angle
A1 from the first axis 654. Such configuration may allow for the
placement of a shockwave source anywhere along the circumference of
a catheter without necessarily being aligned with the
circumferential location of the one more longitudinal grooves of
the catheter.
The low-profile shockwave electrode assembly depicted in FIG. 6A
may be assembled in any suitable fashion. FIGS. 7A-7D depict an
example of a method for making a low-profile shockwave electrode
assembly that is located along a length of an elongate member
(which for clarity purposes, is not shown here). The inner
electrode 700 may be a hypotube that is placed over an exposed core
of a wire 702 and crimped and flattened, as illustrated in FIGS. 7A
and 7B. In some variations, the inner electrode 700 may be crimped
and flattened with a slight curve to approximate and/or match the
radius of curvature of the elongate member. The inner electrode 700
and the wire 702 are then placed within a longitudinal groove of
the elongate member (see FIG. 6A). An insulating layer or sheath
704 may be slid over the elongate member and positioned over the
inner electrode 700 such that an opening 705 of the insulating
sheath 704 is coaxially aligned over the inner electrode, as shown
in FIG. 7C. An outer electrode sheath 706 may be slid over the
elongate member and positioned over the insulating sheath 704 such
that an opening 707 of the outer electrode sheath 706 is coaxially
aligned over the opening 705 of the insulating sheath 704, as shown
in FIG. 7D. In variations of shockwave electrode assemblies that
comprise a second inner electrode circumferentially opposite to the
first inner electrode 700, aligning the openings of the insulating
sheath and the outer electrode over the first inner electrode may
also align a second set of openings of the insulating sheath and
the outer electrode over the second inner electrode. Once the outer
electrode sheath and the insulating sheath have been positioned in
the desired location, their location may be secured by applying a
UV curable adhesive, such as Loctite 349, at both ends of the
sheaths.
FIGS. 8A and 8B depict side and cross-sectional view (taken along
line 8B-8B) of one variation of a grooved elongate member (e.g., a
catheter) that may be used in any of the shockwave devices
described herein. The elongate member 802 may have any number of
longitudinal grooves or channels configured for retaining a wire
and/or inner electrode, and may for instance have 1, 2, 3, 4, 5, 6,
7, 8, 10, etc. grooves. As illustrated in FIG. 6B, the elongate
member 602 has six grooves that surround a central guide wire lumen
603. In some variations, the elongate member 802 may have a radius
of about 0.014 inch and the each of the grooves may have a radius
of curvature of about 0.005 inch to about 0.010 inch. Where the
grooves may have a semi-elliptical shape, the minor axis may be
about 0.008 inch and the minor axis may be about 0.015 inch. The
elongate member 802 may also comprise a guide wire lumen 803, where
the guide wire lumen may have a radius of about 0.0075 inch to
about 0.018 inch, e.g., about 0.02 inch or 0.0175 inch.
Optionally, shrink tubing may be provided over each of the wires to
help retain the wire within the groove while still allowing the
wires to slide and move within the grooves to accommodate bending
of the elongate member 602. Wires slidably disposed within
longitudinal grooves on the outer surface of the elongate member
may retain the flexibility of the elongate member such that the
elongate member may easily navigate and access tortuous
vasculature. While the variations here depict wires that are
slidably disposed within grooves of the elongate member to
accommodate bending of the elongate member, in other variations,
the wires may be conductive elements that are co-extruded with the
elongate member and therefore unable to slide with respect to the
elongate member. However, co-extruding conductive elements with the
elongate member may stiffen the elongate member, thereby limiting
its flexibility and ability to navigate to and access tortuous
vasculature. For example, the smallest radius of curvature
attainable by an elongate member with co-extruded conductive
elements may be larger than the smallest radius of curvature
attainable by an elongate member with wires slidably disposed in
grooves along its outer surface. The turning radius of an elongate
member that has wires slidably disposed within longitudinal grooves
along its outer surface may be tighter than the turning radius of
the same elongate member if the wires were unable to slide with
respect to the elongate member.
The wires retained within the longitudinal grooves of an elongate
member may be connected to inner electrodes, as described above,
and/or may be connected to outer electrode sheaths. A wire that is
retained within a longitudinal groove may be connected to an outer
electrode sheath using any suitable method, for example, by
friction fit and/or adhesives. For example, the wire may be
friction fit between the outer electrode sheath and the insulating
sheath, and optionally further secured in contact with the outer
electrode sheath with an adhesive, as depicted in FIG. 9. As
depicted there, a wire 900 retained within a groove 904 of an
elongate member 902 may contact an outer electrode sheath 906 via a
stripped portion 910 that is drawn out of the groove 904 and
inserted between the outer electrode sheath and insulating sheath
908 (for clarity, the inner electrode of this this shockwave
electrode assembly is not shown). The wire may be secured between
the outer electrode sheath and the insulating sheath friction fit
and may optionally be further secured and electrically insulated by
an adhesive, such as conductive epoxy or laser welded or spot
welded. Inserting the stripped portion 910 (where the electrically
conductive portion is exposed) between the outer electrode sheath
and the insulating sheath and further sealing it with an adhesive
may help to ensure that the wire does not inadvertently contact an
inner electrode or any other conductive medium (e.g., the fluid
that may be used to fill a shockwave angioplasty balloon). Various
connections between the wires and the inner and outer electrodes of
the electrode assemblies are further described below.
The first and second inner electrodes of an electrode assembly may
be connected such that they are each independently
voltage-controlled, e.g., each directly connect to separate
positive channels of a high voltage pulse generator. They may be
independently controlled (e.g., capable of being pulsed separately)
or may be controlled together. An example of direct connectivity
between the first and second inner electrodes of a shockwave
electrode assembly 1000 is depicted in FIGS. 10A-10D. The shockwave
electrode assembly 1000 may be any of the electrode assemblies
described herein, and may comprise a first inner electrode 1002, a
second inner electrode 1004 and an outer electrode 1006. As
schematically depicted in FIG. 7A, a first wire 1003 may connect
the first inner electrode 1002 to a first voltage output port VO1
of a pulse generator 1001. A second wire 1005 may connect the
second inner electrode 1004 to a second voltage output port VO2 of
the pulse generator 1001. A third wire 1006 may connect the outer
electrode to a third voltage output port VO3 (a ground channel or
negative terminal). In some variations, the first voltage output
port VO1 and the second voltage output port VO2 may be positive
channels while the third voltage output port VO3 may be a negative
channel (or vice versa). During a high voltage pulse on the first
and/or second voltage output ports VO1, VO2, current may flow in
the direction of the arrows in the first and/or second wires 1003,
1005 from the voltage outputs VO1, VO2 to the first and second
inner electrodes 1002, 1004. The high voltage pulse generator may
apply a voltage pulse on output port VO1 such that the potential
difference between the first inner electrode 1002 and the outer
electrode 1006 is high enough to form a plasma arc between them,
generating a bubble that gives rise to a shockwave. Similarly, the
high voltage pulse generator may simultaneously or sequentially
apply a voltage pulse on output port VO2 such that the potential
difference between the second inner electrode 1004 and the outer
electrode 1006 is high enough to form a plasma arc between them,
generating a bubble that gives rise to a different shockwave. In a
variation where the first inner electrode and second inner
electrode are located circumferentially opposite to each other
(e.g., 180 degrees apart from each other around the circumference
of the elongate member), the shockwaves generated by the first and
second inner electrodes may propagate in opposite directions,
extending outward from the side of the elongate member. The current
that traverses the bubble from the inner electrode 1002 and/or
inner electrode 1004 to the outer electrode 1006 returns via wire
1007 to voltage output port VO3 (which may be a negative channel or
a ground channel). Voltage output ports VO1 and VO2 may be
independently addressed (e.g., voltage and current may be applied
to one output but not necessarily the other), or may be not be
independently addressed (e.g., activating one output necessarily
activates the other). Optionally, a connector (not shown) may be
provided between the wires 1003, 1005, 1007 and the voltage pulse
generator 1001 so that the wires of the elongate member may be
easily connected to the output ports of the high voltage
generator.
FIGS. 10B-10D depict one variation of how the circuit of FIG. 10A
may be implemented in a shockwave device that comprises the
shockwave electrode assembly 1000. The shockwave device may
comprise a catheter 1010 with a central guide wire lumen 1011 and
six longitudinal grooves (G1-G6) arranged around the guide wire
lumen. FIG. 10B is a top view of the electrode assembly 1000 where
the first inner electrode 1002 is visible and FIG. 10C a bottom
view of the electrode assembly 1000 where the second inner
electrode 1004 is visible. The first and second inner electrodes
are located circumferentially opposite each other (i.e., 180
degrees apart). FIG. 10D depicts the grooves in which each of the
inner electrodes and/or wires may be retained. The return wire 1007
may be connected to the outer electrode sheath 1006 in any of the
configurations described above and may be retained in groove G3.
The wire 1003 connects the first inner electrode 1002 with the
first voltage output VO1, and may be retained in groove G1. The
wire 1005 connects the second inner electrode 1004 with the second
voltage output VO2, and may be retained in groove G4, directly
opposite groove G1. While the example depicted here uses grooves
G1, G3, and G4, it should be understood that any three of the six
grooves may be used to retain the wires 1003, 1005 and 1007 to
attain the connectivity depicted in FIG. 10A. For example, the
wires 1003, 1005 and 1007 may be retained in grooves G2, G5 and G6
respectively, or grooves G3, G6 and G5 respectively, or grooves G1,
G3, and G2 respectively, grooves G1, G3, and G5 respectively,
etc.
Alternatively, the first and second inner electrodes of an
electrode assembly may be connected in series such that activating
the first inner electrode also activates the second inner
electrode. This may allow the electrode assembly to generate up to
two shockwaves (i.e., one from each of the first and second inner
electrodes) using only a single output port on the high voltage
generator. FIGS. 11A-11D depict one example of a shockwave
electrode assembly 1100 that is configured such that first inner
electrode 1102 is in series with the second inner electrode 1104.
The shockwave electrode assembly 1100 may be any of the electrode
assemblies described herein, and may comprise a first inner
electrode 1102, a second inner electrode 1104 and an outer
electrode 1106. As schematically depicted in FIG. 11A, a first wire
1103 may connect the first inner electrode 1102 to a first voltage
output port VO1 of a pulse generator 1101. A second wire 1105 may
connect the second inner electrode 1104 to a second voltage output
port VO2 (a ground channel or negative terminal). In some
variations, the first voltage output port VO1 may be a positive
channel while the second voltage output port VO2 may be a negative
channel (or vice versa). During a high voltage pulse on the first
voltage output port VO1, current may flow in the direction of the
arrow in the first wire 1103 from the voltage output VO1 to the
first inner electrode 1102. The high voltage pulse generator may
apply a voltage pulse on output port VO1 such that the potential
difference between the first inner electrode 1102 and the outer
electrode 1106 is high enough to form a plasma arc between them,
generating a bubble that gives rise to a shockwave. The current
that traverses the bubble from the first inner electrode 1102 to
the outer electrode 1106 may set up a potential difference between
the outer electrode 1106 and the second inner electrode 1004 that
is high enough to form a plasma arc between them, generating a
bubble that gives rise to a different shockwave. In a variation
where the first inner electrode and second inner electrode are
located circumferentially opposite to each other (e.g., 180 degrees
apart from each other around the circumference of the elongate
member), the shockwaves generated by the first and second inner
electrodes may propagate in opposite directions, extending outward
from the side of the elongate member. The current then returns to
the voltage source generator via wire 1105 to voltage output port
VO2 (which may be a negative channel or a ground channel).
Optionally, a connector (not shown) may be provided between the
wires 1103, 1105 and the voltage pulse generator 1101 so that the
wires of the elongate member may be easily connected to the output
ports of the high voltage generator.
FIGS. 11B-11D depict one variation of how the circuit of FIG. 11A
may be implemented in a shockwave device that comprises the
shockwave electrode assembly 1100. The shockwave device may
comprise a catheter 1110 with a central guide wire lumen 1111 and
six longitudinal grooves (G1-G6) arranged around the guide wire
lumen. FIG. 11B is a top view of the electrode assembly 1100 where
the first inner electrode 1102 is visible and FIG. 11C a bottom
view of the electrode assembly 1100 where the second inner
electrode 1104 is visible. The first and second inner electrodes
are located circumferentially opposite each other (i.e., 180
degrees apart). FIG. 11D depicts the grooves in which each of the
inner electrodes and/or wires may be retained. The wire 1103
connects the first inner electrode 1102 with the first voltage
output VO1, and may be retained in groove G1. The wire 1105
connects the second inner electrode 1104 with the second voltage
output VO2, and may be retained in groove G4, directly opposite
groove G1. While the example depicted here uses grooves G1 and G4,
it should be understood that any two of the six grooves may be used
to retain the wires 1103, 1105 to attain the connectivity depicted
in FIG. 11A. For example, the wires 1103 and 1105 may be retained
in grooves G2 and G5 respectively, or grooves G3 and G6
respectively, etc.
Some variations of shockwave devices may comprise two or more
shockwave electrode assemblies. For example, the shockwave
angioplasty system 520 depicted in FIG. 5A comprises two electrode
assemblies where each electrode assembly has two inner electrodes
circumferentially opposite to each other and is configured to
generate two shockwaves that propagate outward from the side of the
catheter in opposite directions. The two shockwave electrode
assemblies may be connected such that each of the inner electrodes
of the two electrode assemblies (i.e., for a total of four inner
electrodes) are each connected to separate voltage channels. For
example, each of the inner electrodes may each be directly
connected to different voltage channels in a direct connect
configuration. The inner electrodes may be individually addressable
and/or can be activated by separate ports on a high voltage pulse
generator. FIGS. 12A-12D depict a variations of two shockwave
electrode assemblies of a shockwave device (e.g., a shockwave
angioplasty device) where the first and second inner electrodes of
each electrode assembly are connected such that they are each
connected to separate voltage channels. The shockwave electrode
assemblies 1200, 1250 may be any of the electrode assemblies
described herein. The first shockwave electrode assembly 1200 may
comprise a first inner electrode 1202, a second inner electrode
1204 and an outer electrode 1206. The second shockwave electrode
assembly 1250 may comprise a first inner electrode 1252, a second
inner electrode 1254 and an outer electrode 1256. As schematically
depicted in FIG. 12A, a first wire 1203 may connect the first inner
electrode 1202 of the first electrode assembly 1200 to a first
voltage output port VO1 of a pulse generator 1201. A second wire
1205 may connect the second inner electrode 1204 of the first
electrode assembly 1200 to a second voltage output port VO2 of the
pulse generator 1201. A third wire 1207 may connect the outer
electrode 1206 of the first electrode assembly to a third voltage
output port VO3 (a ground channel or negative terminal). In some
variations, the first voltage output port VO1 and the second
voltage output port VO2 may be positive channels while the third
voltage output port VO3 may be a negative channel (or vice versa).
A fourth wire 1253 may connect the first inner electrode 1252 of
the second electrode assembly 1250 to a fourth voltage output port
VO4 of the pulse generator 1201. A fifth wire 1255 may connect the
second inner electrode 1254 of the second electrode assembly 1250
to a fifth voltage output port VO5 of the pulse generator 1201. The
outer electrode 1256 of the second electrode assembly may also
contact the third wire 1207 and be connected to the third voltage
output port VO3. In some variations, the first voltage output port
VO1, the second voltage output port VO2, the fourth voltage output
VO4 and the fifth voltage output VO5 may each be positive channels
while the third voltage output port VO3 may be a negative channel.
During a high voltage pulse on any one of the first and/or second
and/or fourth and/or fifth voltage output ports VO1, VO2, VO4, V5,
current may flow in the direction of the arrows in the first and/or
second and/or fourth and/or fifth wires 1203, 1205, 1253, 1255 from
the voltage outputs VO1, VO2, VO4, VO5 to the first and second
inner electrodes of the first and second electrode assemblies 1202,
1204, 1252, 1254 of the first and second electrode assemblies. The
high voltage pulse generator may apply a voltage pulse on any one
of the output ports such that the potential difference between any
one of the inner electrodes and the corresponding outer electrode
1206, 1256 is high enough to form a plasma arc between them,
generating a bubble that gives rise to a shockwave. Each of the
plasma arcs formed between an inner electrode and an outer
electrode (of the same electrode assembly) may generate a bubble
that gives rise to a different shockwave. In a variation where the
first inner electrode and second inner electrode are located
circumferentially opposite to each other (e.g., 180 degrees apart
from each other around the circumference of the elongate member),
the shockwaves generated by the first and second inner electrodes
may propagate in opposite directions, extending outward from the
side of the elongate member. With the two electrode assemblies
1200, 1250, a total of up to four different shockwaves may be
generated. The current that traverses the bubble from the inner
electrodes to the corresponding outer electrode returns via wire
1207 to voltage output port VO3 (which may be a negative channel or
a ground channel). In some variations, the return current from any
one of the outer electrodes may be connected to an intermediate
node (e.g., an optional outer electrode band or sheath, and/or
optional interconnect wire) before it is connected to the wire
1207. The voltage output ports may be independently addressed or
may be not be independently addressed, as previously described.
Optionally, a connector (not shown) may be provided between the
wires and the voltage pulse generator 1201 so that the wires of the
elongate member may be easily connected to the output ports of the
high voltage generator.
FIGS. 12B-12C depict one variation of how the circuit of FIG. 12A
may be implemented in a shockwave device that comprises the first
shockwave assembly 1200 and second shockwave electrode assembly
1250. The shockwave device may comprise a catheter 1210 with a
central guide wire lumen 1211 and six longitudinal grooves (G1-G6)
arranged around the guide wire lumen. FIG. 12B is a perspective
view of the distal portion of the shockwave device with the first
electrode assembly 1200 and second electrode assembly 1250 each at
different longitudinal locations along the catheter 1210. For each
electrode assembly 1200, 1250, the first and second inner
electrodes are located circumferentially opposite each other (i.e.,
180 degrees apart). FIG. 12C depicts the grooves in which each of
the inner electrodes and/or wires may be retained, some of which
are also depicted in FIG. 12B. The return wire 1207 may be
connected to the outer electrode sheaths 1206, 1256 in any of the
configurations described above and may be retained in groove G3.
The wire 1203 connects the first inner electrode 1202 of the first
electrode assembly with the first voltage output VO1, and may be
retained in groove G2. The wire 1205 connects the second inner
electrode 1204 of the first electrode assembly with the second
voltage output VO2, and may be retained in groove G5, directly
opposite groove G2. The wire 1253 connects the first inner
electrode 1252 of the second electrode assembly with the fourth
voltage output VO4, and may be retained in groove G1. The wire 1255
connects the second inner electrode 1254 of the second electrode
assembly with the fifth voltage output VO5, and may be retained in
groove G3, directly opposite groove G1. While the example depicted
here uses grooves G1-G5, it should be understood that any five of
the six grooves may be used to retain the wires to attain the
connectivity depicted in FIG. 12A. For example, the wires 1203,
1205, 1253, 1255 and 1207 may be retained in grooves G1, G4, G2,
G5, G3 respectively, or grooves G5, G3, G1, G4, G5 respectively,
etc. As depicted in FIG. 12B, the circumferential locations of the
inner electrodes of the first electrode assembly are different from
the circumferential locations of the inner electrodes of the second
electrode assembly, i.e., they are offset from each other by an
angle, which angle may be any value of about 1 degree to about 179
degrees, e.g., about 60 degrees, as determined by the location of
the groove in which the inner electrode is retained. However, in
other variations, the inner electrode may span a circumferential
length of the catheter (such as described and depicted in FIG. 6H),
which may allow for the electrode assemblies to be rotated such
that shockwaves may be generated from a desired circumferential
location. In such variations, the orientation of the first and
second electrode assemblies may be the same (i.e., shockwaves may
be generated from the same circumferential location around the
catheter, but longitudinally offset by the distance between the
electrode assemblies).
Alternatively or additionally, two electrode assemblies may be
connected in series with respect to each other such that activating
a first electrode assembly also activates a second electrode
assembly. In some variations, it may be desirable to have multiple
shockwave sources without as many wires running along the elongate
member, and using fewer ports on the voltage pulse generator. For
example, connecting two electrode assemblies in series may allow
the shockwave device to simultaneously generate up to four
different shockwaves using just two voltage output ports (e.g., one
positive channel and one negative channel). In addition, reducing
the number of wires that extend along the length of the elongate
member would allow the elongate member to bend and flex more freely
as it is advanced through the vasculature of a patient (e.g., may
allow for a tighter turning radius). One example of a series
connection between two electrode assemblies 1300, 1350 is depicted
in FIGS. 13A-13D. As schematically depicted in FIG. 13A, a first
wire 1303 may connect the first inner electrode 1302 of the first
electrode assembly to a first voltage output port VO1 of a pulse
generator 1301. A second wire 1305 (e.g., an interconnect wire) may
connect the second inner electrode 1304 of the first electrode
assembly 1300 to a first inner electrode 1352 of the second
electrode assembly 1350. A third wire 1307 may connect the second
inner electrode 1354 to a second voltage output port VO2 (a ground
channel or negative terminal). In some variations, the first
voltage output port VO1 may be a positive channel while the second
voltage output port VO2 may be a negative channel (or vice versa).
During a high voltage pulse on the first voltage output port VO1,
current may flow in the direction of the arrow in the first wire
1303 from the voltage output VO1 to the first inner electrode 1302
of the first electrode assembly 1200. The high voltage pulse
generator may apply a voltage pulse on output port VO1 such that
the potential difference between the first inner electrode 1302 and
the outer electrode 1306 of the first electrode assembly 1300 is
high enough to form a plasma arc between them, generating a bubble
that gives rise to a shockwave. The current that traverses the
bubble from the first inner electrode 1302 to the outer electrode
1306 may set up a potential difference between the outer electrode
1306 and the second inner electrode 1304 that is high enough to
form a plasma arc between them, generating a bubble that gives rise
to a different shockwave (i.e., a second shockwave). In a variation
where the first inner electrode and second inner electrode are
located circumferentially opposite to each other (e.g., 180 degrees
apart from each other around the circumference of the elongate
member), the shockwaves generated by the first and second inner
electrodes may propagate in opposite directions, extending outward
from the side of the elongate member. The current then flows in the
second wire 1305 to the first inner electrode 1352 of the second
electrode assembly 1350 and may set up a potential difference
between the first inner electrode 1352 and the outer electrode 1356
that is high enough to form a plasma arc between them, generating a
bubble that gives rise to another shockwave (i.e., a third
shockwave). The current that traverses the bubble from the first
inner electrode 1352 to the outer electrode 1356 may set up a
potential difference between the outer electrode 1356 and the
second inner electrode 1354 of the second electrode assembly 1350
that is high enough to form a plasma arc between them, generating a
bubble that gives rise to an additional shockwave (i.e., a fourth
shockwave). The current then returns to the voltage source
generator via wire 1307 to voltage output port VO2 (which may be a
negative channel or a ground channel). Optionally, a connector (not
shown) may be provided between the wires 1303, 1307 and the voltage
pulse generator 1301 so that the wires of the elongate member may
be easily connected to the output ports of the high voltage
generator.
FIGS. 13B-13D depict one variation of how the circuit of FIG. 13A
may be implemented in a shockwave device that comprises the first
shockwave electrode assembly 1300 and the second shockwave
electrode assembly 1350. The shockwave device may comprise a
catheter 1310 with a central guide wire lumen 1311 and six
longitudinal grooves (G1-G6) arranged around the guide wire lumen.
FIG. 13B is a top view of the first and second electrode assemblies
1300, 1350 where the first inner electrode 1302 of the first
electrode assembly 1300 and the second inner electrode 1354 of the
second electrode assembly 1352 are visible. FIG. 13C a bottom view
of the first and second electrode assemblies 1300, 1350 where the
second inner electrode 1304 of the first electrode assembly 1300
and the first inner electrode 1356 of the second electrode assembly
1352 are visible. The first and second inner electrodes of each
electrode assembly are located circumferentially opposite each
other (i.e., 180 degrees apart). FIG. 11D depicts the grooves in
which each of the inner electrodes and/or wires may be retained.
The wire 1303 connects the first inner electrode 1302 with the
first voltage output VO1, and may be retained in a proximal length
of groove G4 (i.e., the length of the longitudinal groove that is
proximal to the first electrode assembly). The wire 1305 connects
the second inner electrode 1304 of the first electrode assembly
with the first inner electrode 1352 of the second electrode
assembly and may be retained in groove G1, directly opposite groove
G4. The wire 1307 connects the second electrode 1354 of the second
electrode assembly with the second voltage output VO2, and may be
retained in a distal length of groove G4 (i.e., the length of the
longitudinal groove that is distal to the second electrode
assembly). In some variations, the wire 1307 does not directly
connect to the second voltage output port VO2, but instead connects
with an additional electrode (e.g., an outer electrode sheath),
which is then connected by an additional wire to the second voltage
output port. While the example depicted here uses grooves G1, G4,
it should be understood that any two of the six grooves may be used
to retain the wires 1303, 1305, 1307 to attain the connectivity
depicted in FIG. 13A. For example, the wires 1303, 1305, 1307 may
be retained in grooves G2 and G5 respectively, or grooves G3 and G6
respectively, etc.
Some variations of shockwave devices comprise a plurality of
electrode assemblies, where some of the electrode assemblies are
connected in series, while other electrode assemblies are
configured such that the first inner electrode and the second inner
electrode are each independently voltage-controlled (e.g., each
connected to separate ports on a high voltage pulse generator in a
direct connect configuration). This may allow for more shockwaves
to be simultaneously generated using fewer wires than if all the
electrode assemblies were connected to separate voltage channels.
Reducing the number of wires along the longitudinal length of the
elongate member may help to maintain the ability of the elongate
member to bend and flex (e.g., to navigate through tortuous
vasculature). This may help the elongate member to have a tighter
turning radius, and/or to be able to attain a smaller radius of
curvature. An increased number of wires along the length of the
elongate member may stiffen the elongate member such that it is no
longer able to navigate tortuous vasculature. In some variations,
the shockwave force that is generated from electrode assemblies
that are connected to a plurality of high voltage channels (e.g.,
where each inner electrode is connected to a separate voltage
channel in a direct connect configuration) may be greater than the
shockwave force that is generated from electrode assemblies that
are configured in series. In some variations, the voltage applied
to electrode assemblies connected in series needs to be greater
than the voltage applied to electrode assemblies where each inner
electrode is directly connected to a separate voltage channel in
order to attain a shockwave of similar magnitude. In some
variations, the voltage pulse applied to electrodes in a series
configuration may be longer than the voltage pulse applied to
electrodes in a direct connect configuration in order to generate
shockwaves of similar magnitude. A shockwave device that has a
combination of electrode assemblies in both series and direct
connect circuit configurations may provide the ability to apply a
stronger shockwave when desired, but also have the ability to
simultaneously apply many shockwaves without substantially
compromising the flexibility and turning capability of the catheter
by minimizing the number of wires.
Some shockwave devices may have at least one electrode assembly
configured such that its two inner electrodes are connected to
separate high voltage channels (i.e., a direct connect
configuration) and at least one electrode assembly configured such
that its two inner electrodes are connected in series. In still
other variations, a shockwave device may have at least one
electrode assembly configured such that its two inner electrodes
are connected to separate high voltage channels and two or more
electrode assemblies that are connected in series. A schematic of a
shockwave device that uses both electrode assemblies that are
connected in series and in a direct connect configuration is
depicted in FIGS. 14A-14G. A shockwave device may have five
electrode assemblies located along its length and an elongate
member (e.g., a catheter with a longitudinal guide wire lumen) with
six grooves extending along its length. The electrode assemblies
may be any of the electrode assemblies described herein, and may,
for example, each have a first and second inner electrode, an
insulating sheath disposed over the inner electrodes, the
insulating sheath having first and second openings aligned over the
first and second inner electrodes, and an outer electrode sheath
disposed over the insulating sheath, the outer electrode sheath
having first and second openings aligned over the first and second
inner openings of the insulating sheath. The openings of the outer
electrode may be larger than the openings of the insulating sheath,
and may be coaxially aligned with the openings of the insulating
sheath such that the center of the openings are aligned along the
same axis. The first and second electrode assemblies 1400, 1420 may
be connected in series and controlled together as a pair, and the
fourth and fifth electrode assemblies 1440, 1450 may be connected
in series and controlled together as a pair, separately from the
first and second electrodes. The series connections may be similar
to the connection described and depicted in FIGS. 13A-13D. The
inner electrodes of the third electrode assembly (which may be
located in between the two pairs of series connected electrode
assemblies, with the first and second electrode assemblies on one
side and the fourth and fifth electrode assemblies on the other
side) may be connected in a direct connect configuration, similar
to the connected described and depicted in FIGS. 10A-10D. The
series connections between the first electrode assembly 1400 and
the second electrode assembly 1420 may comprise a first wire 1403
connecting a first voltage output port VO1 to the first inner
electrode 1402 of the first electrode assembly 1400, a second wire
1405 (e.g., an interconnect wire) connecting the second inner
electrode 1404 of the first electrode assembly to the first inner
electrode 1422 of the second electrode assembly 1420, and a third
wire 1407 connecting the second inner electrode 1424 of the second
electrode assembly to a voltage output port VO5. The third wire
1407 may be part of the current return path to the voltage pulse
generator. The series connections between the fourth electrode
assembly 1440 and the fifth electrode assembly 1450 may comprise a
sixth wire 1413 connecting a fourth voltage output port VO4 to the
first inner electrode 1442 of the fourth electrode assembly 1440, a
seventh wire 1415 (e.g., an interconnect wire) connecting the
second inner electrode 1444 of the fourth electrode assembly to the
first inner electrode 1452 of the fifth electrode assembly 1450,
and the third wire 1407 connecting the second inner electrode 1454
of the fifth electrode assembly to the voltage output port VO5. The
direct connect configuration of the third electrode assembly 1430
may comprise a fourth wire 1409 connecting a second voltage output
port VO2 to the first inner electrode 1432 and a fifth wire 1411
connecting a third voltage output port VO3 to the second inner
electrode 1434. The outer electrode 1436 may be connected to the
voltage output port VO5 via the wire 1407.
FIGS. 14B-14G depict one variation of how the circuit of FIG. 14A
may be implemented in a shockwave device comprising five shockwave
electrode assemblies 1400, 1420, 1430, 1440, 1450. The shockwave
device may comprise a catheter with a central guide wire lumen and
six longitudinal grooves arranged around the guide wire lumen. FIG.
14B is perspective view of the five shockwave assemblies 1400,
1420, 1430, 1440, 1450 along the distal portion of the catheter.
The shockwave device depicted there may have a proximal marker band
and a distal marker band (e.g., such as angioplasty marker bands).
FIG. 14C is a close-up view of the first shockwave electrode
assembly 1400, the second shockwave electrode assembly 1420, and
the third shockwave assembly 1430. As described above, the first
and second electrode assemblies 1400, 1420 may be connected in
series, where the wires 1403, 1405, 1407 and inner electrodes 1402,
1404, 1422, 1424 are retained within two of the six grooves, and
may for example, be similar to the configuration depicted in FIGS.
13B-13D. Applying a high voltage pulse on wire 1403 may generate
four radial shockwaves propagating from circumferentially opposite
sides of the catheter. Two of the shockwaves may originate at a
longitudinal location along the catheter corresponding to the
location of the first electrode assembly 1400 and the other two
shockwaves may originate at a longitudinal location along the
catheter corresponding to the location of the second electrode
assembly 1420. FIG. 14D is a close-up view of the fourth shockwave
electrode assembly 1440, the fifth shockwave electrode assembly
1450, and a distal radiopaque marker band 1460. As described above,
the fourth and fifth electrode assemblies 1440, 1450 may be
connected in series, where the wires 1413, 1415, 1407 and inner
electrodes 1442, 1444, 1452, 1454 are retained within two of the
six grooves, and may for example, be similar to the configuration
depicted in FIGS. 13B-13D. In some variations, the wires and inner
electrodes may be in a pair of grooves that are different from the
pair of grooves retaining the wires and inner electrodes of the
first and second electrode assemblies. Applying a high voltage
pulse on wire 1413 may generate four radial shockwaves propagating
from circumferentially opposite sides of the catheter. Two of the
shockwaves may originate at a longitudinal location along the
catheter corresponding to the location of the fourth electrode
assembly 1440 and the other two shockwaves may originate at a
longitudinal location along the catheter corresponding to the
location of the fifth electrode assembly 1450.
FIG. 14E is a close-up view of the fifth electrode assembly 1450
and the distal marker band 1460. In some variations of shockwave
devices, the wire connected to the second inner electrode 1454 of
the fifth electrode assembly 1450 may be connected to the distal
marker band 1460. The distal marker band 1460 may act as a common
node for wires that carry the return currents from the electrode
assemblies, which may help reduce the number of wires carrying a
return current back to the high voltage pulse generator. There may
be several of such return path nodes along the length of the
catheter, and may be, for example, one or more additional
radiopaque marker bands, and/or one or more outer electrode sheaths
of certain electrode assemblies.
FIG. 14F is a close-up view of the third electrode assembly 1430.
As described above, the inner electrode 1432 and inner electrode
1434 (which is not visible in this view) may be in a direct connect
configuration such that they may be individually driven by separate
outputs from the voltage generator. The currents from the inner
electrodes may flow to the outer electrode 1436, which may return
the current to the high voltage pulse generator via the third wire
1407. Alternatively, or additionally, the current from the outer
electrode 1436 may return to the high voltage pulse generator via
an eighth wire 1461. The eighth wire 1461 may be retained in a
groove that is opposite the groove that retains the third wire
1407. FIG. 14G depicts the wires 1409, 1411, 1461 retained within
three grooves of the catheter, where the wires 1409, 1411 are
connected to the inner electrodes 1432, 1434, and retained in
grooves that are opposite to each other. The wire 1461 may contact
the outer electrode 1436 and may be retained in a third groove
(similar to the configuration described and depicted in FIGS.
10A-10D).
While FIGS. 14A-14F depict a shockwave device with five electrode
assemblies located along the length of the elongate member, it
should be understood that a shockwave device may have any number of
electrode assemblies connected in any combination of series and
direct connect configurations. For example, a shockwave device may
have two electrode assemblies that are connected to each other in
series, which may allow for the synchronized generation of four
different shockwaves simultaneously. Alternatively, a shockwave
device may have two electrode assemblies where the two inner
electrodes of each assembly are each connected to separate high
voltage channels in a direct connect configuration, which may allow
for the independent generation of four different shockwaves, either
simultaneously or sequentially. The number of electrode assemblies
along the length of the elongate member of a shockwave device may
be selected according to the geometry of the target tissue region.
For example, a shockwave device intended for breaking up calcified
plaques along a long vessel segment may have five electrode
assemblies along its length, while a device for breaking up plaques
in a shorter vessel segment may have two electrode assemblies along
its length.
Any of the shockwave assemblies described herein may be used in an
angioplasty procedure for breaking up calcified plaques accumulated
along the walls of a vessel. One variation of a method may comprise
advancing a guide wire from an entry site on a patient (e.g., an
artery in the groin area of the leg) to the target region of a
vessel (e.g., a region having calcified plaques that need to be
broken up). A shockwave device comprising a catheter with a guide
wire lumen, one or more low-profile electrode assemblies located
along a length of the catheter, and a balloon may be advanced over
the guide wire to the target region of the vessel. The shockwave
electrode assemblies may be any of the low-profile electrode
assemblies described herein. The balloon may be collapsed over the
catheter while the device is advanced through the vasculature. The
location of the shockwave device may be determined by x-ray imaging
and/or fluoroscopy. When the shockwave device reaches the target
region, the balloon may be inflated by a fluid (e.g., saline and/or
saline mixed with an image contrast agent). The one or more
electrode assemblies may then be activated to generate shockwaves
to break up the calcified plaques. The progress of the plaque
break-up may be monitored by x-ray and/or fluoroscopy. The
shockwave device may be moved along the length of the vessel if the
calcified region is longer than the length of the catheter with the
electrode assemblies, and/or if the calcified region is too far
away from the electrode assemblies to receive the full force of the
generated shockwaves. For example, the shockwave device may be
stepped along the length of a calcified vessel region to
sequentially break up the plaque. The electrode assemblies of the
shockwave device may be connected in series and/or may be connected
such that each inner electrode is connected to separate high
voltage channels, and may be activated simultaneously and/or
sequentially, as described above. For example, a pair of electrode
assemblies may be connected in series and activated simultaneously,
while another electrode assembly may be connected such that each
inner electrode is connected to separate high voltage channels, and
activated sequentially and/or simultaneously. Once the calcified
region has been sufficiently treated, the balloon may be inflated
further or deflated, and the shockwave device and guide wire may be
withdrawn from the patient.
It will be understood that the foregoing is only illustrative of
the principles of the invention, and that various modifications,
alterations and combinations can be made by those skilled in the
art without departing from the scope and spirit of the invention.
Any of the variations of the various shockwave devices disclosed
herein can include features described by any other shockwave
devices or combination of shockwave devices herein. Furthermore,
any of the methods can be used with any of the shockwave devices
disclosed. Accordingly, it is not intended that the invention be
limited, except as by the appended claims. For all of the
variations described above, the steps of the methods need not be
performed sequentially.
* * * * *